Hong Kong (CNN) -- North Korea appeared to have conducted its third underground nuclear bomb test Tuesday, officials and experts said, as U.S. seismologists reported activity centered near the site of the secretive regime's two previous atomic blasts.

Although North Korea had warned the world of its plans to carry out a new test in a vitriolic statement last month, the move is still likely to rattle the security situation in Northeast Asia as analysts try to determine the power and complexity of the device the North is thought to have detonated.

If confirmed, it would be the first nuclear test under the North's young leader, Kim Jong Un, who appears to be sticking closely to his father's policy of building up the isolated state's military deterrent to keep its foes at bay, shrugging off the resulting international condemnation and sanctions.

It also provided a provocative reminder of a seemingly intractable foreign policy challenge for President Barack Obama ahead of his State of the Union address later Tuesday.

The area around the reported epicenter of the magnitude 4.9 disturbance in northeastern North Korea has little or no history of earthquakes or natural seismic hazards, according to U.S. Geological Survey maps. The disturbance Tuesday took place at a depth of about 1 kilometer, the USGS said.

Officials suspect a nuclear test

Government officials and security analysts had little doubt about the cause of the quake.

"We believe North Korea conducted its third nuclear test," said Kim Min-seok, a spokesman for the South Korean defense ministry. He added that the magnitude of the "artificial tremor" suggested the size of the blast was in the order of 6 to 7 kilotons, more powerful than the North's two prior nuclear tests. Read on...

Repugnacan'tTea Party people do not deal in facts ... they never need facts nor real life experience to get in the way of whatever may spew forth from their mouth and since all of it is BS they can just go off in 10 different directions at once with even more BS ... FAUX Network will have it in a loop 24/7 for their viewers ...

It sounds like you're subscribing to Putin's soviet-style propaganda about fascists in Ukraine. Russia fought off Hitler's armies on their own soil. No doubt the emotional scars are still on the Russian psyche. If Putin can sell the idea Russia is fighting fascists on their borders again to the average hung over Russian schmo, he has megatons of political capital to spend. He's actually projecting his own tendencies onto the Ukrainians. Have you forgotten the Ukrainians fought Hitler's armies as well, sir? If you have proof there is a sizable fascist streak in the Ukraine (as Putin would love for there to be) you are more than welcome to present it. I'm sure Putin would try to discredit any opposition to him in the strongest terms possible, a position we may hold in common.